Douglas,
> Did you read World Bank Article article you cited?
>
> WBA> The Manila-based IRRI is currently working on transferring the
> WBA> genes required for beta carotene biosynthesis into the popular
> WBA> tropical indica rices preferred by most Asian consumers and
> WBA> suited to tropical growing conditions, **using traditional
> WBA> breeding techniques.** [emphasis added]
I believe that all these high carotenoid rices are transgenic. The initial
transformation was done with Japonica rice (see attached abstract). IRRI is
transferring the trait into the more important Indica rices using ordinary
backcrossing.
> The question is: By means of which genetic strategy? Recombinant
> (micro-surgical)? Or sexual? If you were a sexed organism, which would
> you prefer?
You embrace a natural-law ethics that is common in the sustainable ag
community. I maintain it is a fallacy and an illusion. Just about
everything that humans do, from medicine to agriculture can be attacked on
the basis of natural law. This whole perspective is a byproduct of
human/nature dualism IMO. Dinking around with nature (grafting, selfing,
tillage etc.) is natural as can be. I don't mean to imply everything is
safe or effective, just that natural-law ethics is a poor foundation.
Dale
AU: Burkhardt,-P.K.; Beyer,-P.; Wunn,-J.; Kloti,-A.; Armstrong,-G.A.;
Schledz,-M.; Lintig,-J.-von.; Potrykus,-I.
TI: Transgenic rice (Oryza sativa) endosperm expressing daffodil (Narcissus
pseudonarcissus) phytoene synthase accumulates phytoene, a key intermediate
of provitamin A biosynthesis.
SO: Plant-j. Oxford : Blackwell Sciences Ltd. May 1997. v. 11 (5) p.
1071-1078..
CN: DNAL QK710.P68
LA: English
AB: Rice (Oryza sativa L.), the major food staple for more than two billion
people, contains neither beta-carotene (provitamin A) nor C40 carotenoid
precursors thereof in its endosperm. To improve the nutritional value of
rice, genetic engineering was chosen as a means to introduce the ability to
make beta-carotene into rice endosperm tissue. Investigation of the
biochemical properties of immature rice endosperm using [14C]-labelled
substrates revealed the presence of geranyl geranyl diphosphate, the C20
general isoprenoid precursor necessary for C40 carotenoid biosynthesis.
Phytoene synthase, which condenses two molecules of geranyl geranyl
diphosphate, is the first of four specific enzymes necessary for
beta-carotene biosynthesis in plants. Therefore, the Japonica rice model
variety Taipei 309 was transformed by microprojectile bombardment with a
cDNA coding for phytoene synthase from daffodil (Narcissus pseudonarcissus)
under the control of either a constitutive or an endosperm-specific
promoter. In transgenic rice plants, the daffodil enzyme is active, as
measured by the in vivo accumulation of phytoene in rice endosperm. Thus, it
is demonstrated for the first time that it is in principle possible to
engineer a critical step in provitamin A biosynthesis in a
non-photosynthetic, carotenoid-lacking plant tissue. These results have
important implications for long-term prospects of overcoming worldwide
vitamin A deficiency.
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